USPTO Patents Application 08873597

CLAIMS

We claim:

1 . A method for detecting the presence of a target sequence in a nucleic acid sa
comprising

5 a) applying a first input signal comprising an AC component and a/fion-zero DC

component to a hybridization complex, said hybridization complex comprising at
least a target sequence and a first probe single stranded nucjeic acid, said
hybridization complex being covalently attached to:

i) a first electron transfer moiety comprising^n electrode; and
10 ii) a second electron transfer moiety; and

b) detecting the presence of said hybridization complex by receiving an output
signal characteristic of electron transfer through said hybridization complex.

2. A method for detecting the presence of>a target sequence in a nucleic acid sample,
comprising

1 5 a) applying a first input sigi^coryif)rising an AC component at a first frequency

and a non-zero DC component to a hybridization complex, said hybridization
complex comprising at/feast a target sequence and a first probe single stranded
nucleic acid, said hybridization complex being covalently attached to:
i) a first electron transfer moiety comprising an electrode; and

20 ii) a second electron transfer moiety;

b) applying a second input signal comprising an AC component at least a "second
frequencVand a non-zero DC component to said hybridization complex; and

c) detecting the presence of said hybridization complex by receiving an output
signal^ characteristic of electron transfer through said hybridization complex.

25 3. A method for detecting the presence of a target sequence in a nucleic acid sample,
comprising

/ a) applying a first input signal comprising an AC component and a first non-zero
DC component to a hybridization complex, said hybridization complex comprising

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n

10

at least a target sequence and a first probe single stranded nucleic acid, saic
hybridization complex being covalently attached to:

i) a first electron transfer moiety comprising an electrode; and

ii) a second electron transfer moiety;
5 b) applying a second input signal comprising said AC component and at least a

second non-zero DC component to said hybridization complex; and
c) detecting the presence of said hybridization complex hyreceiving an output
signal characteristic of electron transfer through said hybridization complex.

4. A method for detecting the presence of a target sequence in a nucleic acid sample,
10 comprising

a) applying a first input signal comprising^n AC component at a first voltage
amplitude

to a hybridization complex, said hybridization complex comprising at least a target
sequence and a first probe single strand^a nucleic acid, said hybridization complex being
1 5 covalently attached to :

i) a first electron transfer rrfbiety comprising an electrode; and

ii) a second electron transfer moiety;

b) applying a second input signal comprising said AC component at a second
voltage amplitude to said hybridization complex; and

20 c) detecting the presence of said hybridization complex by receiving an output

signal characteristic of electron transfer through said hybridization complex.

5. A method according to claim 4 wherein said input signals further comprise a non-zero
DC componer

6. A method according to claims 1, 2, 3 or 4, wherein said hybridization complex
25 comprises

a) a single stranded nucleic acid covalently attached to:

1) a first electron transfer moiety comprising an electrode; and

2) a second electron transfer moiety; and

b) a target sequence hybridized to said single stranded nucleic acid.

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7. A method according to claims 1, 2, 3 or 4 wherein said hybridization complex
comprises:

a) a single stranded nucleic acid covalently attached via a conductive oligomer to a
first electron transfer moiety comprising an electrode; and
5 b) a target sequence hybridized to said single stranded nucleic acid; ;

i) a second electron transfer moiety.

8. A method according to claims 1 , 2, 3 or 4 wherein said output ^sfgnal comprises a
current.

9. A method according to claims 1, 2, 3 or 4 wherein SEji# output signal comprises a
10 voltage.

10. A method according to claims 1,2, Vo* 4/Wherein said output signal comprises a
phase shift between said input and said quttmt signafls.

1 1 . A method according to claims 1^2, 3 or 4 wherein said output signal comprises a
change in the faradaic impedance between the electron transfer moieties as a result of the

12. A method according to claims 1, 2, 3 or 4 further comprising adding said target
sequence to said single stranded nucleic acid to form said hybridization complex.

13. A method according to claims 1, 3 or 4 further comprising applying input signal at a
plurality of frequencies.

20 14. A method according to claims 1, 2 or 4 further comprising applying signal at a
plurality of DC voltages.

15^/A method according to claims 1, 2, 3 or 4 wherein said single-stranded nucleic acid is
covalently attached to said electrode via a spacer.

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4 •

16. A method according to claim 15, wherein said spacer is a conductiy^polymer.

17. A method according to claim 1 5, wherein said conductive polymer has the formula:

wherein f / ,

Y is an aromatic group; /v^x
n is an integer from 1 to 50; /
g is either 1 or zero; /
e is an integer from zero to 1 0;and
m is zero or 1; /

wherein when g i^l , B-D is a conjugated bond; and

wherein when/g is zero, e is 1 and D is preferably carbonyl, or a heteroatom moiety,
wherein the heteroatom is selected from oxygen, sulfur, nitrogen or phosphorus.

18/A method according to claim 15, wherein said electrode further comprises a
monolayer.

19. An apparatus for the detection of target nylcleic acids in a test sample, comprising:

a) a test chamber comprising a first and a second measuring electrode, wherein said
first measuring electrode comprises/a covalently attached conductive oligomer
covalently attached to a single strknded nucleic acid; and

b) an AC/DC voltage source electrically connected to said test chamber.

20. An apparatus for the detection of target nucleic acids in a test sample, comprising:

a) a test chamber comprising a first and a second measuring electrode, wherein said
first measuring electrode comprises a covalently attached single stranded nucleic
acid comprising a covalently attached second electron transfer moiety; and

b) an AC/DC voltage source electrically connected to said test chamber.

21. An apparatus according to claim 19 or 20, further comprising:

d) a processor coupled to said electrodes.

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•

22. An apparatus according to claim 19 or 20, wherein said AC voltage source is capable
of delivering frequencies from between about4 Hz to about 100 kHz.

23. An apparatus according to claim 22; wherein said single stranded nucleic acids are
covalently attached to said electrodp^via a spacer.

. An apparatus according to claim Jft, wherein said spacer is a conductive oligomer.

5. An apparatus according to claim 19 or fe4, wherein said conductive oligomer has the
formula:

wherein

Y is an aromatic group;
n is an integer from 1 to 50;
g is either 1 or zero;
e is an integer from zero to 1 $and
m is zero or 1 ;

wherein when g is 1, B-D/is a conjugated bond; and

wherein when g is zero ? /e is 1 and D is preferably carbonyl, or a heteroatom moiety,
wherein the heteroatom is selected from oxygen, sulfur, nitrogen or phosphorus.

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ID